To me this sounds great, no more freezing summers! Go on, join up as a volunteer and help save the world ! Wellington could become like Australia's Sunshine Coast while Aucklanders will swelter in Cairns-style heat if climate change predictions prove accurate. The first results from the world's biggest climate-change modelling experiment predict that global temperatures could rise by 11 degrees celsius – double the estimates produced so far. "Our experiment shows that increased levels of greenhouse gases could have a much greater impact on climate than previously thought," said the project's chief scientist, David Stainforth from Oxford University. Scientists estimate these levels will be reached by the middle of this century if greenhouse gas emissions are not reduced. About 95,000 people from 150 countries – including 494 New Zealanders – are taking part in the climate prediction.net experiment to explore the possible impact of global warming. By downloading free software from www.climateprediction.net on their personal computers, participants run their own unique version of Britain's Met Office climate model. While their computer is idle, the program runs a climate simulation over days or weeks and automatically reports the results to Oxford University and other collaborating institutions around the world. Together, the volunteers have simulated more than four million model years, donated 8000 years of computer time and exceeded the processing power of the world's biggest supercomputers. The first results of the continuing experiment are reported in the science journal Nature. The temperature range predicted is based on assumptions of carbon dioxide levels double those found before the Industrial Revolution. However, Niwa climate scientist Jim Salinger treated the predictions with caution yesterday. "It's a very interesting result. I wouldn't pass a judgment on it at this stage." The current United Nations Intergovernmental Panel on Climate Change projections put the likely temperature rise at between 1.4 degrees celsius and 5.8 degrees, he said. New Zealand's climate would change completely if temperatures rose 11C, forcing major changes to agriculture. There could also be more flooding as the Antarctic and Greenland ice sheets melted. New Zealand would become a sub-tropical to tropical climate, Dr Salinger said. Dunedin would have a mean temperature of 20C similar to Brisbane.